{"product_id":"harley-davidson-x440-genuine-cylinder-head-gasket-hdh12251acj000s","title":"Harley-Davidson X440 Genuine Cylinder Head Gasket – HDH12251ACJ000S | Fits X440, X440 OBDII \u0026 X440T","description":"\u003ch2\u003eHarley-Davidson X440 Genuine Cylinder Head Gasket – HDH12251ACJ000S | Fits X440, X440 OBDII \u0026amp; X440T\u003c\/h2\u003e\n\n\u003cp\u003eIf you are opening the top end of your \u003cstrong\u003eHarley-Davidson X440\u003c\/strong\u003e, this \u003cstrong\u003eHDH12251ACJ000S\u003c\/strong\u003e is the genuine OEM \u003cstrong\u003ecylinder head gasket\u003c\/strong\u003e you should match before reassembly. Your official EPC screenshot identifies it as \u003cstrong\u003eGASKET CYLINDER HEAD\u003c\/strong\u003e, shows an MRP of \u003cstrong\u003e₹320\u003c\/strong\u003e, and confirms fitment for \u003cstrong\u003eX440 (Sept, 2023)\u003c\/strong\u003e, \u003cstrong\u003eX440 OBDII (May, 2025)\u003c\/strong\u003e, and \u003cstrong\u003eX440T (Jan, 2026)\u003c\/strong\u003e. Public seller pages also list the same part number as \u003cstrong\u003eGASKET CYLINDER HEAD (HDH12251ACJ000S)\u003c\/strong\u003e at the same ₹320 price point, which supports both the code match and the public market identity of the part.\u003c\/p\u003e\n\n\u003cp\u003eIn buyer language, this part is commonly searched as the \u003cstrong\u003eX440 head gasket\u003c\/strong\u003e, \u003cstrong\u003ecylinder head gasket\u003c\/strong\u003e, \u003cstrong\u003etop head gasket\u003c\/strong\u003e, \u003cstrong\u003etop-end gasket\u003c\/strong\u003e, or \u003cstrong\u003eengine head sealing gasket\u003c\/strong\u003e. Buyers usually replace it during cylinder head removal, piston work, top-end rebuilds, compression repair, overheating-related repair, or when fixing leaks after the engine has been opened. Unlike low-cost paper gaskets, a head gasket is a critical sealing part and should never be reused once disturbed.\u003c\/p\u003e\n\n\u003cp\u003eThis page is written to rank for the exact part code \u003cstrong\u003eHDH12251ACJ000S\u003c\/strong\u003e and real buyer searches like \u003cstrong\u003eHarley X440 head gasket\u003c\/strong\u003e, \u003cstrong\u003eX440 cylinder head gasket\u003c\/strong\u003e, and \u003cstrong\u003eX440 top end gasket\u003c\/strong\u003e.\u003c\/p\u003e\n\n\u003ch3\u003eWhat This Product Is\u003c\/h3\u003e\n\u003cp\u003eThis is the \u003cstrong\u003egenuine cylinder head gasket\u003c\/strong\u003e for the Harley-Davidson X440 engine platform. In practical buyer language, this is the top-end sealing gasket installed between the cylinder and cylinder head during engine assembly.\u003c\/p\u003e\n\n\u003ch3\u003eVerified Compatibility\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\u003cstrong\u003eHarley-Davidson X440 (Sept, 2023)\u003c\/strong\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003cstrong\u003eHarley-Davidson X440 OBDII (May, 2025)\u003c\/strong\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003cstrong\u003eHarley-Davidson X440T (Jan, 2026)\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eImportant Fitment Note\u003c\/h3\u003e\n\u003cp\u003eThis listing is kept conservative and tied to the exact models visible in your official catalogue screenshot. Do not assume fitment for other 440-family engines unless the exact part number matches. A cylinder head gasket must always be purchased by exact code, not by visual similarity.\u003c\/p\u003e\n\n\u003ch3\u003eWhy Buyers Need It\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eHelps seal combustion pressure, oil passages, and mating surfaces correctly during top-end reassembly\u003c\/li\u003e\n  \u003cli\u003eReduces risk of compression loss or leakage after rebuild work\u003c\/li\u003e\n  \u003cli\u003eUseful during cylinder head removal, piston work, and engine repair\u003c\/li\u003e\n  \u003cli\u003eCritical genuine sealing part that must be replaced during reassembly\u003c\/li\u003e\n  \u003cli\u003eBetter sealing confidence than unknown local gasket alternatives\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eGenuine OEM part number:\u003c\/strong\u003e HDH12251ACJ000S\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePart identity in EPC:\u003c\/strong\u003e GASKET CYLINDER HEAD\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eConfirmed fitment from EPC:\u003c\/strong\u003e X440, X440 OBDII, X440T\u003c\/li\u003e\n  \u003cli\u003e\u003cstrong\u003ePublic seller listing matches same code and price point\u003c\/strong\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003cstrong\u003eEssential top-end engine sealing part\u003c\/strong\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003cstrong\u003eRelevant during head removal and top-end rebuild work\u003c\/strong\u003e\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMRP shown in catalogue:\u003c\/strong\u003e ₹320\u003c\/li\u003e\n  \u003cli\u003e\u003cstrong\u003eBest bought only by exact part number match\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eCommon Purchase Reasons\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eCylinder head removed during service\u003c\/li\u003e\n  \u003cli\u003ePiston or valve-train work\u003c\/li\u003e\n  \u003cli\u003eCompression repair or leak-related repair\u003c\/li\u003e\n  \u003cli\u003eOld head gasket damaged during dismantling\u003c\/li\u003e\n  \u003cli\u003ePreventive replacement during reassembly\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhy Genuine Matters\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eHead gasket profile, thickness, and passage cut-outs must match exactly\u003c\/li\u003e\n  \u003cli\u003eIncorrect gasket specification can affect compression, sealing, and engine reliability\u003c\/li\u003e\n  \u003cli\u003eBetter fit confidence than generic sheet-cut or uncertain aftermarket alternatives\u003c\/li\u003e\n  \u003cli\u003eCritical part where repeat labor costs can far exceed gasket cost\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eFitment \/ Return Prevention Note\u003c\/h3\u003e\n\u003cp\u003ePlease buy this only after matching the exact part number \u003cstrong\u003eHDH12251ACJ000S\u003c\/strong\u003e. Engine gaskets should never be ordered by appearance alone. Confirm the application by EPC, VIN, or engine teardown requirement before purchase.\u003c\/p\u003e\n\n\u003ch3\u003eWhat’s in the Box\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\u003cstrong\u003e1 x Cylinder Head Gasket\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eInstallation \u0026amp; Workshop Notes\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eClean both mating surfaces fully before installing the new gasket\u003c\/li\u003e\n  \u003cli\u003eDo not reuse a head gasket after dismantling\u003c\/li\u003e\n  \u003cli\u003eCheck head flatness, cylinder surface, studs, and related components during top-end work\u003c\/li\u003e\n  \u003cli\u003eUse the correct torque sequence and torque values during reassembly\u003c\/li\u003e\n  \u003cli\u003eAfter assembly, inspect for leaks and confirm proper compression behavior\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTechnical Details\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCustomer-facing brand:\u003c\/strong\u003e Harley-Davidson X440 Genuine\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCatalogue \/ backend source:\u003c\/strong\u003e Hero-supported official parts catalogue\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e HDH12251ACJ000S\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eProduct Name:\u003c\/strong\u003e Gasket Cylinder Head\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eConfirmed Models:\u003c\/strong\u003e X440, X440 OBDII, X440T\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePack Quantity:\u003c\/strong\u003e 1 piece\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMRP:\u003c\/strong\u003e ₹320\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eBuyer-Focused FAQs\u003c\/h3\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ1. What is HDH12251ACJ000S used for?\u003c\/strong\u003e\u003cbr\u003e\nIt is the genuine \u003cstrong\u003ecylinder head gasket\u003c\/strong\u003e, used when the cylinder head is refitted to help seal combustion pressure and the top end of the engine properly.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ2. Which bikes does it fit?\u003c\/strong\u003e\u003cbr\u003e\nYour official catalogue screenshot confirms \u003cstrong\u003eX440\u003c\/strong\u003e, \u003cstrong\u003eX440 OBDII\u003c\/strong\u003e, and \u003cstrong\u003eX440T\u003c\/strong\u003e.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ3. Should I reuse the old head gasket?\u003c\/strong\u003e\u003cbr\u003e\nNo. A head gasket should be replaced once the engine is opened. Reusing it increases the risk of poor sealing, compression issues, and leaks.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ4. Is this the same as the cylinder gasket?\u003c\/strong\u003e\u003cbr\u003e\nNo. Cylinder gasket and cylinder head gasket are different sealing parts used at different interfaces in the top end.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ5. Why buy genuine for this part?\u003c\/strong\u003e\u003cbr\u003e\nBecause correct gasket profile and thickness matter. A genuine head gasket is critical to rebuild quality and long-term sealing reliability.\u003c\/p\u003e\n\n\u003ch3\u003eSEO Tags\u003c\/h3\u003e\n\u003cp\u003eHDH12251ACJ000S, Harley X440 head gasket, X440 cylinder head gasket, Harley-Davidson X440 top end gasket, X440 engine head gasket, genuine X440 head gasket, X440 rebuild gasket, X440 OBDII head gasket\u003c\/p\u003e","brand":"Harley-Davidson","offers":[{"title":"Default Title","offer_id":51304971698471,"sku":"HDH12251ACJ000S","price":0.0,"currency_code":"INR","in_stock":true}],"url":"https:\/\/underthehood.co.in\/products\/harley-davidson-x440-genuine-cylinder-head-gasket-hdh12251acj000s","provider":"UNDER THE HOOD","version":"1.0","type":"link"}